Valve opening and closing timing control device

ABSTRACT

A valve opening and closing timing control device includes: a drive-side rotary body rotating synchronously with a crankshaft; a driven-side rotary body provided inside the drive-side rotary body coaxial with the drive-side rotary body and rotating integrally with a camshaft; advance and retard chambers formed between the drive-side and driven-side rotary bodies; a valve unit including a spool and controlling supply and discharge of fluid to and from the advance and retard chambers; a tubular valve case having an internal space extending along the rotation axis inside the driven-side rotary body and housing the valve unit; first and second drain flow paths through which the fluid is discharged from one and the other of the advance and retard chambers, respectively, through the spool. The first drain and second drain flow paths extend in directions intersecting each other at different positions in the rotation axis direction.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U.S.C. § 119to Japanese Patent Application 2019-221341, filed on Dec. 6, 2019, theentire content of which is incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to a valve opening and closing timing controldevice that controls opening and closing timing of a valve.

BACKGROUND DISCUSSION

A valve opening and closing timing control device includes a drive-siderotary body that rotates synchronously with a crankshaft of an internalcombustion engine, and a driven-side rotary body that is arrangedcoaxially with a rotation axis of the drive-side rotary body and rotatesintegrally with a camshaft for opening and closing a valve. By supplyingfluid to and discharging fluid from an advance chamber and a retardchamber formed between the drive-side rotary body and the driven-siderotary body, a relative rotation phase between the drive-side rotarybody and the driven-side rotary body is controlled. It is known that thevalve opening and closing timing control device includes a valve unitthat controls the supply of the fluid to and discharge of the fluid fromthe advance chamber and the retard chamber, and a coupling bolt thathouses the valve unit in an internal space in a direction along therotation axis (for example, see JP-A-2018-91226 (Reference 1)).

In the valve opening and closing timing control device described inReference 1, as the valve unit, a sleeve, a spool movable in therotation axis direction, and a fluid supply pipe are arranged in orderfrom an outer side to an inner side in a radial direction in theinternal space of the coupling bolt. Further, the valve opening andclosing timing control device includes a lock mechanism that can switchbetween a lock state in which the valve opening and closing timingcontrol device is restrained to an intermediate phase between a mostretarded phase and a most advanced phase and a lock release state inwhich the restraint of the intermediate phase is released.

Reference 1 discloses an embodiment in which, in the lock state, a lockdrain flow path through which the fluid is discharged from the lockmechanism extends in the rotation axis direction of the coupling bolt,and an advance chamber drain flow path through which the fluid isdischarged from the advance chamber extends in the rotation axisdirection of the coupling bolt as a flow path different from the lockdrain flow path. The lock drain flow path also serves as a retardchamber drain flow path through which the fluid is discharged from theretard chamber. That is, the advance chamber drain flow path and theretard chamber drain flow path extending in the rotation axis directionare arranged at different positions in a circumferential direction onthe coupling bolt.

In the valve opening and closing timing control device described inReference 1, a plurality of drain flow paths in the rotation axisdirection are extended to the coupling bolt. Accordingly, a flow pathcross-sectional area of the advance chamber drain flow path and theretard chamber drain flow path for phase control is limited. As aresult, at the time of the phase control, a speed at which the fluid isdischarged from the advance chamber or the retard chamber may bereduced, and responsiveness of the phase control may be deteriorated.

A need thus exists for a valve opening and closing timing control devicewhich is not susceptible to the drawback mentioned above.

SUMMARY

A characteristic configuration of a valve opening and closing timingcontrol device according to an aspect of this disclosure resides in thatthe valve opening and closing timing control device includes adrive-side rotary body that rotates synchronously with a crankshaft ofan internal combustion engine; a driven-side rotary body that isprovided inside the drive-side rotary body in a state of being coaxialwith a rotation axis of the drive-side rotary body and that rotatesintegrally with a camshaft for opening and closing a valve; an advancechamber and a retard chamber formed between the drive-side rotary bodyand the driven-side rotary body; a valve unit that includes a spoolmovable in a rotation axis direction and that controls supply anddischarge of fluid to and from the advance chamber and the retardchamber; a tubular valve case that has an internal space extending alongthe rotation axis inside the driven-side rotary body in a radialdirection and that houses the valve unit in the internal space; a firstdrain flow path through which the fluid is discharged from any one ofthe advance chamber or the retard chamber through the spool; and asecond drain flow path through which the fluid is discharged from theother one of the advance chamber or the retard chamber through thespool, in which the first drain flow path and the second drain flow pathextend in directions intersecting each other at different positions inthe rotation axis direction.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and additional features and characteristics of thisdisclosure will become more apparent from the following detaileddescription considered with the reference to the accompanying drawings,wherein:

FIG. 1 is a cross-sectional view showing a valve opening and closingtiming control device;

FIG. 2 is a cross-sectional view taken along a line II-II of FIG. 1;

FIG. 3 is a diagram listing a relationship between a position of a spooland supply and discharge of working oil;

FIG. 4 is a cross-sectional view of a valve unit in which the spool isin a first advance position;

FIG. 5 is a cross-sectional view of the valve unit in which the spool isin a second advance position;

FIG. 6 is a cross-sectional view of the valve unit in which the spool isin a neutral position;

FIG. 7 is a cross-sectional view of the valve unit in which the spool isin a retard position;

FIG. 8 is a cross-sectional view showing a valve opening and closingtiming control device according to a first alternative embodiment;

FIG. 9 is a cross-sectional view showing a valve opening and closingtiming control device according to a second alternative embodiment;

FIG. 10 is a cross-sectional view taken along a line X-X of FIGS. 8 and9; and

FIG. 11 is a diagram listing a relationship between a position of aspool and supply and discharge of working oil according to anotherembodiment.

DETAILED DESCRIPTION

Embodiments of a valve opening and closing timing control devicedisclosed here will be described below with reference to the drawings.However, this disclosure is not limited to the following embodiments,and various modifications can be made without departing from the scopeof this disclosure.

[Basic Configuration]

As shown in FIGS. 1 and 2, a valve opening and closing timing controldevice A includes an external rotor 20 as a drive-side rotary body, aninternal rotor 30 as a driven-side rotary body, and an electromagneticcontrol valve V that controls supply and discharge of working oil as aworking fluid. Since the valve opening and closing timing control deviceA sets an opening and closing timing (opening and closing period) of anintake camshaft 5 (an example of a camshaft) of an engine E (an exampleof an internal combustion engine) of a vehicle such as a passenger car,the valve opening and closing timing control device A is providedcoaxially with a rotation axis X of the intake camshaft 5.

The internal rotor 30 (an example of the driven-side rotary body) isarranged coaxially with the rotation axis X of the intake camshaft 5(external rotor 20), and is integrally rotated with the intake camshaft5 by being coupled to the intake camshaft 5 by a coupling bolt 40 (anexample of a valve case). The internal rotor 30 is provided inside theexternal rotor 20. The external rotor 20 (an example of the drive-siderotary body) is arranged coaxially with the rotation axis X and rotatessynchronously with a crankshaft 1 of the engine E. With thisconfiguration, the external rotor 20 and the internal rotor 30 arerelatively rotatable.

The valve opening and closing timing control device A includes a lockmechanism L that holds a relative rotation phase between the externalrotor 20 and the internal rotor 30 (hereinafter simply referred to as“relative rotation phase”) at an intermediate lock phase M (an exampleof an intermediate phase) shown in FIG. 2. The intermediate lock phase Mis a phase between a most retarded phase and a most advanced phase. Thevalve opening and closing timing control device A is controlled to shiftto the intermediate lock phase M at the time of stop control of theengine E as an opening and closing timing suitable for starting theengine E. The shift control to the intermediate lock phase M may beexecuted when the engine E is started.

The electromagnetic control valve V includes an electromagnetic unit Vaand a valve unit Vb supported by the engine E.

The electromagnetic unit Va includes a solenoid portion 50 and a plunger51 that is arranged coaxially with the rotation axis X and protrudes andretracts by drive control of the solenoid portion 50. In the valve unitVb, a spool 55 that controls the supply and discharge of the working oil(an example of fluid) is arranged coaxially with the rotation axis X,and has a position relationship set such that a protrusion end of theplunger 51 abuts against an outer end of the spool 55.

The electromagnetic control valve V sets a protrusion amount of theplunger 51 by controlling electric power supplied to the solenoidportion 50, and operates the spool 55. By this operation, theelectromagnetic control valve V controls a flow of the working oil toset an opening and closing timing of an intake valve 5V, and performsswitching between a lock state in which the lock mechanism L isrestrained to the intermediate lock phase M and a lock release state inwhich the restraint of the intermediate lock phase M is released. Aconfiguration and a control mode of the electromagnetic control valve Vwill be described later.

As shown in FIG. 1, the engine E is a four-cycle type engine in which apiston 3 is housed in a cylinder bore of a cylinder block 2 at an upperposition, and the piston 3 and the crankshaft 1 are coupled by acoupling rod 4. An upper portion of the engine E includes the intakecamshaft 5 for opening and closing the intake valve 5V and an exhaustcamshaft (not shown).

A support member 10 that rotatably supports the intake camshaft 5 isformed with a supply flow path 8 through which the working oil issupplied from a hydraulic pump P driven by the engine E. The hydraulicpump P supplies lubricating oil stored in an oil pan of the engine E tothe valve unit Vb as the working oil through the supply flow path 8.

A timing chain 7 is wound around an output sprocket 6 formed on thecrankshaft 1 of the engine E and a timing sprocket 21S of the externalrotor 20. Accordingly, the external rotor 20 rotates synchronously withthe crankshaft 1. A sprocket is also provided at a front end of theexhaust camshaft on an exhaust side, and the timing chain 7 is alsowound around the sprocket.

As shown in FIG. 2, the external rotor 20 rotates in a drive rotationdirection S by a driving force from the crankshaft 1. A direction inwhich the internal rotor 30 rotates relative to the external rotor 20 inthe same direction as the drive rotation direction S is referred to asan advance direction Sa, and a reverse direction to the direction isreferred to as a retard direction Sb. In the valve opening and closingtiming control device A, a relationship between the crankshaft 1 and theintake camshaft 5 is set such that an intake compression ratio isincreased as a displacement amount when the relative rotation phase isdisplaced in the advance direction Sa increases, and the intakecompression ratio is reduced as a displacement amount when the relativerotation phase is displaced in the retard direction Sb increases.

The present embodiment describes the valve opening and closing timingcontrol device A provided on the intake camshaft 5. The valve openingand closing timing control device A may be provided on the exhaustcamshaft, and may be provided on both the intake camshaft 5 and theexhaust camshaft.

As shown in FIG. 1, the external rotor 20 includes an external rotorbody 21, a front plate 22, and a rear plate 23, which are integrated byfastening a plurality of fastening bolts 24. The timing sprocket 21S isformed on an outer periphery of the external rotor body 21.

As shown in FIG. 2, a plurality of (three in the present embodiment)protrusion portions 21T protruding inward in a radial direction areintegrally formed on the external rotor body 21. The internal rotor 30includes a columnar internal rotor body 31 that is in close contact withthe protrusion portions 21T of the external rotor body 21, and aplurality of vane portions 32 (three in the present embodiment)protruding outward in the radial direction from an outer periphery ofthe internal rotor body 31 so as to come into contact with an innerperipheral surface of the external rotor body 21.

As described above, the internal rotor 30 is provided inside theexternal rotor 20, and a plurality of (three in the present embodiment)fluid pressure chambers C are formed on an outer peripheral side of theinternal rotor body 31 at positions between a pair of protrusionportions 21T adjacent to each other in the rotation direction. The fluidpressure chambers C are partitioned by the vane portions 32, and thusadvance chambers Ca and retard chambers Cb are partitioned. Further, theinternal rotor body 31 is formed with advance flow paths 33communicating with the advance chambers Ca and retard flow paths 34communicating with the retard chambers Cb.

As shown in FIGS. 1 and 2, the lock mechanism L includes a lock member25 that is supported to be freely protruded and retracted in the radialdirection with respect to each of the two protrusion portions 21T of theexternal rotor 20, a lock spring 26 that protrudes and biases the lockmember 25, and a lock recess 27 formed on the outer periphery of theinternal rotor body 31. A lock control flow path 35 communicating withthe lock recess 27 is formed in the internal rotor body 31.

The lock mechanism L functions to regulate the relative rotation phaseto the intermediate lock phase M by simultaneously engaging the two lockmembers 25 with the corresponding lock recesses 27 by a biasing force ofthe lock spring 26. By supplying the working oil to the lock controlflow path 35 in this lock state, the lock member 25 is disengaged fromthe lock recess 27 against the biasing force of the lock spring 26 torelease the lock state (lock release state). Conversely, by dischargingthe working oil from the lock control flow path 35, the lock member 25that receives the biasing force of the lock spring 26 is engaged withthe lock recess 27 to allow the lock member 25 to shift to the lockstate.

The lock mechanism L may be configured by engaging the single lockmember 25 with the corresponding single lock recess 27. Further, thelock mechanism L may have a configuration in which the lock member 25 isguided so as to move in the rotation axis X direction.

[Coupling Bolt]

As shown in FIGS. 1 and 4, the coupling bolt 40 (an example of the valvecase) is integrally formed with a bolt body 41 which is generallytubular and a bolt head 42 on an outer end side (left side in FIG. 4).An internal space 40R that runs in the rotation axis X direction isformed inside the coupling bolt 40, and a male screw portion 41S isformed on an outer periphery of an inner end side (right side in FIG. 4)of the bolt body 41. An annular constriction portion 41A, which is anannular groove along the outer periphery of the bolt body 41, is formedon an outer end side of the bolt body 41 adjacent to the male screwportion 41S.

As shown in FIG. 1, the intake camshaft 5 defines an axial internalspace 5R centered on the rotation axis X, and a female screw portion 5Sis formed on an inner periphery of the axial internal space 5R. Theaxial internal space 5R communicates with the supply flow path 8 and issupplied with the working oil from the hydraulic pump P.

With this configuration, the bolt body 41 is inserted into the internalrotor 30, the male screw portion 41S is screwed to the female screwportion 5S of the intake camshaft 5, and the internal rotor 30 isfastened to the intake camshaft 5 by the rotation operation of the bolthead 42. By the fastening, the internal rotor 30 is fixed to the intakecamshaft 5, and the axial internal space 5R and the internal space 40Rof the coupling bolt 40 (strictly, an internal space of a fluid supplypipe 54) communicate with each other.

As shown in FIG. 4, a regulation wall 44 is formed on the outer end sideof the inner peripheral surface of the internal space 40R of thecoupling bolt 40 in the rotation axis X direction. The regulation wall44 protrudes in a direction of approaching the rotation axis X. Theregulation wall 44 regulates a protrusion position by abutting a landportion 55 b on an outer end side of the spool 55, which will bedescribed later. In a region from an intermediate position of thecoupling bolt 40 to an end portion on the outer end side thereof, aplurality of (four in the present embodiment) first drain flow paths D1are formed in an elongated hole shape (an example of a hole portion)with one end blocked along the rotation axis X.

In the bolt body 41, a plurality of lock ports 41 c (four in the presentembodiment) communicating with the lock control flow path 35, aplurality of (four in the present embodiment) advance ports 41 acommunicating with the advance flow path 33, and a plurality of (four inthe present embodiment) retard ports 41 b communicating with the retardflow path 34 are formed as through holes connecting the internal space40R and the outer peripheral surface in order from the outer end side tothe inner end side of the coupling bolt 40 (see also FIG. 1). On aninner end side of the retard port 41 b of the bolt body 41, a pluralityof (four in the present embodiment) second drain flow paths D2 areformed as through holes connecting the internal space 40R and the outerperipheral surface, and communicate with the annular constrictionportion 41A. The annular constriction portion 41A communicates with adrain communication path 5A formed through the end portion of the intakecamshaft 5, and the working oil from the second drain flow path D2 isdischarged to the outside through the drain communication path 5A (seealso FIG. 1). That is, in the present embodiment, due to theconfiguration in which the first drain flow path D1 extends in therotation axis X direction and the second drain flow path D2 extends inthe radial direction orthogonal to the rotation axis X direction, thefirst drain flow path D1 and the second drain flow path D2 extend indirections intersecting each other at different positions in therotation axis X direction. The drain communication path 5A may be formedat an end portion of the internal rotor 30, or may be formed at aboundary position between the internal rotor 30 and the intake camshaft5.

[Valve Unit]

As shown in FIGS. 1 and 4, the valve unit Vb includes the fluid supplypipe 54 that is coaxial with the rotation axis X and is housed in theinternal space 40R, and the spool 55 that is freely slidable in therotation axis X direction while being guided by the inner peripheralsurface of the coupling bolt 40 and an outer peripheral surface of apipeline portion 54T of the fluid supply pipe 54. The valve unit Vbincludes a spool spring 56 as a biasing member that biases the spool 55in the protrusion direction, a check valve CV, an oil filter 59, and afixing ring 60.

The fluid supply pipe 54 includes the pipeline portion 54T inserted inthe spool 55 and a flange-shaped base end portion 54S at which the innerend side of the pipeline portion 54T is bent in an annular shape. Thepipeline portion 54T and the base end portion 54S are integrally formed.The base end portion 54S abuts on a regulation step portion 41D providedat a boundary position on the inner peripheral side between the malescrew portion 41S and the annular constriction portion 41A of thecoupling bolt 40. In the pipeline portion 54T, a plurality of (three inthe present embodiment) first supply ports 54 a are formed near the baseend portion 54S, and a plurality of (three in the present embodiment)second supply ports 54 b are formed on the outer end side of the firstsupply ports 54 a.

The three first supply ports 54 a are wide in the circumferentialdirection and have an elongated hole shape extending in the rotationaxis X direction. Four intermediate hole portions 55 c formed in thespool 55 at positions corresponding to the first supply ports 54 a arecircular. From such a configuration, the working oil from the pipelineportion 54T can be reliably supplied to the intermediate hole portions55 c.

Similar to the first supply ports 54 a, the second supply ports 54 balso have an elongated hole shape extending in the rotation axis Xdirection. Four end hole portions 55 d formed in the spool 55 atpositions corresponding to the second supply ports 54 b are circular.From such a configuration, the working oil can be reliably supplied fromthe pipeline portion 54T to the end hole portions 55 d.

The spool 55 is formed with a spool body 55 a which is tubular and hasan abutting surface formed on the outer end side, and four land portions55 b formed on the outer periphery thereof in a protruding state. Aninternal flow path is formed inside the spool 55. A plurality of (fourin the present embodiment) intermediate hole portions 55 c communicatingwith the internal flow path are formed at an intermediate position ofthe pair of land portions 55 b on an inner end side in the rotation axisX direction. A plurality of (four in the present embodiment) end holeportions 55 d communicating with the internal flow path are formed atthe intermediate position of the pair of land portions 55 b on an outerend side in the rotation axis X direction. An intermediate annulargroove 55 f that does not communicate with the internal flow path isformed at the intermediate position of the pair of land portions 55 bbetween the intermediate hole portion 55 c and the end hole portion 55d. An elongated groove-shaped end annular groove 55 g that does notcommunicate with the internal flow path is formed on an inner end sideof the land portion 55 b on an innermost end side in the rotation axis Xdirection.

The spool 55 is formed with an abutting end portion 55 r that abuts onthe base end portion 54S of the fluid supply pipe 54 to determine anoperation limit when the spool 55 is operated in a pushing direction.The abutting end portion 55 r is provided at an end portion of a regionwhere the spool body 55 a is extended. Even when the spool 55 is pushedin with an excessive force, a defect that the spool 55 operates beyondthe operation limit is prevented.

The spool spring 56 is a compression coil type spring, and is arrangedbetween a bottom wall 55 e on an outer end side of the spool 55 and abottom wall 54Ta on an outer end side of the pipeline portion 54T of thefluid supply pipe 54. When the electric power is not supplied to thesolenoid portion 50 of the electromagnetic unit Va due to an action ofthe biasing force, the land portion 55 b on the outer end side abuts onthe regulation wall 44 and the spool 55 is maintained at a first advanceposition PA1 shown in FIG. 4.

[Check Valve]

The check valve CV includes an opening plate 57 and a valve plate 58which are formed of metal plates having an equal outer diameter, a guidemember 61, a tubular member 62, and a valve spring 63. An annularopening portion 57 a centered on the rotation axis X is formed at anouter peripheral position of the opening plate 57. A circular valve body58 a having a diameter larger than that of the opening portion 57 a isarranged at the outer peripheral position of the valve plate 58, and acircular opening portion 58 b centered on the rotation axis X is formedat a center position.

The guide member 61 includes a bottom portion 61 a and a tubularprotrusion portion 61 b protruding from the bottom portion 61 a. Aplurality of slits 61 ba are formed on a side wall of the protrusionportion 61 b. The protrusion portion 61 b is inserted into the openingportion 58 b of the valve plate 58, and the valve plate 58 is guided bythe protrusion portion 61 b and moves. The tubular member 62 includes abottom portion 62 a and an annular portion 62 b that protrudes annularlyfrom an outer periphery of the bottom portion 62 a. An opening portion62 a 1 having substantially the same diameter as the inner diameter ofthe pipeline portion 54T of the fluid supply pipe 54 is formed at thecenter of the bottom portion 62 a. The opening plate 57, the valve plate58, the guide member 61, and the valve spring 63 are housed inside theannular portion 62 b, and the oil filter 59 abuts on the end portion ofthe annular portion 62 b.

The valve spring 63 is a compression coil type spring and is arrangedbetween the bottom portion 61 a of the guide member 61 and the valvebody 58 a of the valve plate 58. The check valve CV is configured suchthat, when pressure downstream increases or when discharge pressure ofthe hydraulic pump P decreases, the valve body 58 a comes into closecontact with the opening plate 57 by the biasing force of the valvespring 63 to close the opening portion 57 a.

The oil filter 59 has a structure in which a metal net body isreinforced with a resin frame, and removes dust contained in the workingoil. The fixing ring 60 is press-fitted and fixed to an inner peripheryof the end portion of the coupling bolt 40, and positions of the oilfilter 59, the opening plate 57, and the valve plate 58 are determinedby the fixing ring 60. The tubular member 62, the guide member 61, thevalve spring 63, the opening plate 57, and the valve plate 58constituting the check valve CV are arranged in this order, the oilfilter 59 is arranged in the internal space 40R so as to be furtheroverlapped, and the fixing ring 60 is press-fitted and fixed to theinner periphery of the internal space 40R.

In this way, by fixing with the fixing ring 60, the base end portion 54Sof the fluid supply pipe 54 is sandwiched and fixed between the boltbody 41 and the tubular member 62. Due to the biasing force of the spoolspring 56 that abuts on the bottom wall 54Ta of the fluid supply pipe54, the land portion 55 b on the outer end side of the spool 55 abuts onthe regulation wall 44, and a position in the rotation axis X directionis determined.

[Operation Mode]

In the valve opening and closing timing control device A, when theelectric power is not supplied to the solenoid portion 50 of theelectromagnetic unit Va, no pressing force acts on the spool 55 from theplunger 51, and a position of the spool 55 is maintained in a statewhere the land portion 55 b at the outer side position abuts on theregulation wall 44 by the biasing force of the spool spring 56 as shownin FIG. 4.

A movement start position of the spool 55 is the first advance positionPA1. By increasing the electric power supplied to the solenoid portion50 of the electromagnetic unit Va, as shown in FIG. 3, the spool 55 canbe freely operated to the second advance position PA2, the neutralposition PN, and the retard position PB in this order. That is, bysetting the electric power supplied to the solenoid portion 50 of theelectromagnetic unit Va, the spool 55 can be operated to any one of thefour operation positions. When the spool 55 is operated to the retardposition PB, the spool 55 is at the movement end position that maximizesthe electric power supplied to the solenoid portion 50.

Further, in the valve unit Vb, the first advance position PA1 is set toa lock position. In this lock position, the lock mechanism L can shiftto the lock state. When the spool 55 is operated to one of the firstadvance position PA1 and the second advance position PA2, the workingoil supplied from the hydraulic pump P is sent to the advance port 41 athrough the intermediate hole portion 55 c of the spool 55, and isfurther supplied to the advance chamber Ca from the advance flow path33. At the same time, the working oil in the retard chamber Cb flowsfrom the retard flow path 34 to the retard port 41 b, and is dischargedfrom the second drain flow path D2 through the end annular groove 55 gof the spool 55 to the outside through the annular constriction portion41A and the drain communication path 5A.

In the first advance position PA1, as shown in FIG. 4, in cooperationwith the supply of the working oil to the advance chamber Ca and thedischarge of the working oil from the retard chamber Cb, the working oilin the lock recess 27 flows from the lock control flow path 35 to thelock port 41 c, and is discharged from the first drain flow path D1through the intermediate annular groove 55 f of the spool 55. As aresult, when the vane portion 32 of the internal rotor 30 moves in theadvance direction Sa and reaches the intermediate lock phase M, the lockmember 25 engages with the lock recess 27 by the biasing force of thelock spring 26 to be in the lock state.

In the second advance position PA2, as shown in FIG. 5, in cooperationwith the supply of the working oil to the advance chamber Ca, theworking oil flows from the lock port 41 c to the lock recess 27 throughthe lock control flow path 35, and the pressure of the working oil isapplied to the lock member 25. As a result, the operation in the advancedirection Sa is continuously performed in a state where the lock of thelock mechanism L is released.

When the spool 55 is operated to the neutral position PN, as shown inFIG. 6, the pair of land portions 55 b are in such a positionrelationship that the advance port 41 a and the retard port 41 b areclosed, and the supply and discharge of the working oil to the advancechamber Ca and the retard chamber Cb are cut off, and the relativerotation phase is maintained. In the neutral position PN, the workingoil flows from the lock port 41 c to the lock recess 27 through the lockcontrol flow path 35, the pressure of the working oil is applied to thelock member 25, and the state where the lock of the lock mechanism L isreleased continues.

When the spool 55 is operated to the retard position PB, as shown inFIG. 7, the working oil supplied from the hydraulic pump P is sent tothe retard port 41 b through the intermediate hole portion 55 c of thespool 55, and is further supplied to the retard chamber Cb from theretard flow path 34. At the same time, the working oil in the advancechamber Ca flows from the advance flow path 33 to the advance port 41 a,and is discharged from the first drain flow path D1 through theintermediate annular groove 55 f of the spool 55.

In this way, in any of the four operation positions, the working oil ofthe lock mechanism L and the working oil of the advance chamber Ca orthe retard chamber Cb are not discharged to the first drain flow path D1at the same time, and the same applies to the second drain flow path D2.Therefore, it is possible to smoothly discharge the working oil from thelock mechanism L and to reliably shift to the lock state. In addition,it is possible to smoothly discharge the working oil from the advancechamber Ca or the retard chamber Cb to improve the responsiveness of thephase control.

In the present embodiment, the first drain flow path D1 through whichthe working oil is discharged from the advance chamber Ca through thespool 55 and the second drain flow path D2 through which the working oilis discharged from the retard chamber Cb through the spool 55 extend indirections intersecting each other at different positions in therotation axis X direction of the coupling bolt 40. As a result, it ispossible to sufficiently ensure locations for providing the drain flowpaths D1 and D2 on the coupling bolt 40, and it is possible to increasea flow path cross-sectional area of the first drain flow path D1 and thesecond drain flow path D2. Therefore, the flow path cross-sectional areaof the drain flow paths D1 and D2 through which the working oil isdischarged from the advance chamber Ca or the retard chamber Cb can beincreased to improve the responsiveness of the phase control. Inaddition, since the discharge of the working oil from the lock mechanismL is also used in the first drain flow path D1, it is not necessary toseparately provide a lock drain flow path extending in the rotation axisX direction of the coupling bolt 40, so that a sufficient flow pathcross-sectional area of the first drain flow path D1 can be ensured.

Hereinafter, only a configuration different from the above-describedembodiment will be described as other embodiments. In order tofacilitate understanding of the drawings, the same members as those inthe embodiment described above are denoted by the same referencenumerals.

First Alternative Embodiment

As the lock mechanism L in the above-described embodiment, aconfiguration that locks at a most advanced phase or a most retardedphase may be adopted instead of the configuration that locks at theintermediate lock phase M. An embodiment that locks at the most retardedphase is shown in FIGS. 8 to 11. As shown in FIGS. 8 and 10, acommunication path 29 for communicating the lock recess 27 and theadvance chamber Ca is provided. Working oil is supplied or discharged tothe lock recess 27 through the communication path 29 in cooperation withsupply or discharge of the working oil to the advance chamber Ca. In thepresent embodiment, as in the above-described embodiment, the lock port41 c of the bolt body 41 and the end hole portion 55 d of the spool 55are not provided so that an axial length of the valve opening andclosing timing control device A can be shortened to achieve a compactsize.

In the present embodiment, the spool 55 has three operation positions(see FIG. 11). That is, a movement start position of the spool 55 is anadvance position PA. By increasing electric power supplied to thesolenoid portion 50 of the electromagnetic unit Va, the spool 55 can befreely operated to the neutral position PN and the retard position PBincluding a movement end position of the spool 55 in this order.

In the advance position PA of the spool 55, in cooperation with thesupply of working oil to the advance chamber Ca, the working oilsupplied to the advance chamber Ca is also supplied to the lock recess27 through the communication path 29 (see FIGS. 8 and 10). At the sametime, the working oil in the retard chamber Cb flows from the retardflow path 34 to the retard port 41 b, and is discharged from the seconddrain flow path D2 through the end annular groove 55 g of the spool 55to the outside through the annular constriction portion 41A and thedrain communication path 5A. As a result, the operation in the advancedirection Sa is continuously performed in a state where the lock of thelock mechanism L is released. When the spool 55 is operated to theneutral position PN, the supply and discharge of the working oil to theadvance chamber Ca and the lock recess 27 and the retard chamber Cb arecut off, and the relative rotation phase is maintained.

When the spool 55 is operated to the retard position PB, the working oilis supplied to the retard chamber Cb, and in cooperation with thedischarge of the working oil from the advance chamber Ca, the workingoil in the lock recess 27 flows from the advance flow path 33 to theadvance port 41 a through the communication path 29, and is dischargedfrom the first drain flow path D1 through the intermediate annulargroove 55 f of the spool 55. As a result, when the vane portion 32 ofthe internal rotor 30 moves in the retard direction Sb and reaches themost retarded phase, the lock member 25 engages with the lock recess 27by the biasing force of the lock spring 26 to be in the lock state (seeFIG. 10).

Second Alternative Embodiment

In the present embodiment, as shown in FIG. 9, a plurality of draingrooves 55 ba (an example of the outer end portion) are formed on anouter surface of the land portion 55 b on an outer end side of the spool55. The drain grooves 55 ba communicate with the intermediate annulargroove 55 f of the spool 55. That is, the first drain flow path D1 inthe first alternative embodiment is formed between an outer end of thespool 55 including the drain groove 55 ba and the bolt body 41. Similarto the embodiments described above, the second drain flow path D2 in thepresent embodiment is constituted by a through hole (through holeconnecting the internal space 40R of the bolt body 41 and the outerperipheral surface of the bolt body 41) of the bolt body 41 in adirection intersecting the rotation axis X direction.

Since the advance position PA and the neutral position PN of the spool55 are the same as those in the first alternative embodiment, adescription thereof will be omitted. When the spool 55 is operated tothe retard position PB, the working oil is supplied to the retardchamber Cb, and in cooperation with the discharge of the working oilfrom the advance chamber Ca, the working oil in the lock recess 27 flowsfrom the advance flow path 33 to the advance port 41 a through thecommunication path 29, and is discharged from the first drain flow pathD1 including the drain groove 55 ba through the intermediate annulargroove 55 f of the spool 55. As a result, when the vane portion 32 ofthe internal rotor 30 moves in the retard direction Sb and reaches themost retarded phase, the lock member 25 engages with the lock recess 27by the biasing force of the lock spring 26 to be in the lock state.

Other Embodiments

(1) If the first drain flow path D1 and the second drain flow path D2 inthe above-described embodiments extend in directions intersecting eachother at different positions in the rotation axis X direction, the firstdrain flow path D1 may be inclined with respect to the rotation axis Xdirection, or the second drain flow path D2 may be inclined with respectto the radial direction.

(2) In the above-described embodiments, the bolt body 41 is fixed to theintake camshaft 5 by screwing the male screw portion 41S formed on thebolt body 41 of the coupling bolt 40 as a tubular valve case into thefemale screw portion 5S of the intake camshaft 5. Alternatively, forexample, the valve unit Vb and the check valve CV may be housed in thetubular valve case fixed to the intake camshaft 5 by press-fitting orthe like.

(3) The first advance position PA1 described above may be set as themovement end position of the spool 55, and the retard position PB may beset as the movement start position of the spool 55. When the retardposition PB is the movement end position of the spool 55, a lock modemay be provided in which, in cooperation with the discharge of theworking oil from the advance chamber Ca and the supply of working oil tothe retard chamber Cb, the working oil of the lock recess 27 flows fromthe lock control flow path 35 to the lock port 41 c and is dischargedfrom the first drain flow path D1 through the intermediate annulargroove 55 f of the spool 55. In this case, the working oil from theadvance chamber Ca and the working oil from the lock mechanism L aredischarged from the first drain flow path D1 at the same time. The spool55 has five operation positions in which a lock mode at the retardposition is added to the above four operation positions.

(4) The advance position PA in the first and second alternativeembodiments described above may be set as the movement end position ofthe spool 55, and the retard position PB may be set as the movementstart position of the spool 55.

(5) As compared with the embodiments described above, the valve unit Vbmay be configured such that the arrangement of the advance port 41 a andthe retard port 41 b is reversed.

(6) In the embodiments described above, the first drain flow path D1 maybe constituted by a through hole of the coupling bolt 40 in a directionintersecting the rotation axis X direction.

(7) The lock mechanism L in the embodiments described above can berestrained by any one of the intermediate lock phase M, the mostretarded phase, and the most advanced phase. Alternatively, the lockmechanism L may be a multi-lock system capable of restraining therelative rotation phase at a plurality of phases.

INDUSTRIAL APPLICABILITY

Embodiments disclosed here can be used in a valve opening and closingtiming control device that controls a relative rotation phase between adrive-side rotary body and a driven-side rotary body by fluid pressure.

A characteristic configuration of a valve opening and closing timingcontrol device according to an aspect of this disclosure resides in thatthe valve opening and closing timing control device includes adrive-side rotary body that rotates synchronously with a crankshaft ofan internal combustion engine; a driven-side rotary body that isprovided inside the drive-side rotary body in a state of being coaxialwith a rotation axis of the drive-side rotary body and that rotatesintegrally with a camshaft for opening and closing a valve; an advancechamber and a retard chamber formed between the drive-side rotary bodyand the driven-side rotary body; a valve unit that includes a spoolmovable in a rotation axis direction and that controls supply anddischarge of fluid to and from the advance chamber and the retardchamber; a tubular valve case that has an internal space extending alongthe rotation axis inside the driven-side rotary body in a radialdirection and that houses the valve unit in the internal space; a firstdrain flow path through which the fluid is discharged from any one ofthe advance chamber or the retard chamber through the spool; and asecond drain flow path through which the fluid is discharged from theother one of the advance chamber or the retard chamber through thespool, in which the first drain flow path and the second drain flow pathextend in directions intersecting each other at different positions inthe rotation axis direction.

In this configuration, since the valve unit is provided in the internalspace of the valve case in the rotation axis direction inside thedriven-side rotary body in the radial direction, the device can achievea compact size compared with a case where the valve unit is providedoutside the driven-side rotary body. When a single spool is constitutedas in the valve opening and closing timing control device described inReference 1 in order to achieve a more compact size, a flow pathconfiguration of the advance chamber and the retard chamber arecomplicated. Accordingly, it is important to ensure a flow pathcross-sectional area of a phase control drain flow path (advance chamberdrain flow path and retard chamber drain flow path) in order to improvethe responsiveness of the phase control.

Therefore, in this configuration, for example, the first drain flow paththrough which the fluid is discharged from the advance chamber throughthe spool and the second drain flow path through which the fluid isdischarged from the retard chamber through the spool extend indirections intersecting each other at different positions in therotation axis X direction. As a result, it is possible to sufficientlyensure locations for providing the drain flow path, and it is possibleto increase the flow path cross-sectional area of the first drain flowpath and the second drain flow path. Therefore, it is possible toprovide the valve opening and closing timing control device capable ofincreasing the flow path cross-sectional area of the drain flow paththrough which the fluid is discharged from the advance chamber or theretard chamber to improve the responsiveness of the phase control.

Another characteristic configuration resides in that, in the valve case,the first drain flow path is formed to extend in the rotation axisdirection and the second drain flow path is formed to extend in a radialdirection orthogonal to the rotation axis direction.

As in this configuration, in the valve case, when the first drain flowpath extends in the rotation axis direction and the second drain flowpath extends in the radial direction and both drain flow paths areorthogonal to each other, the flow path cross-sectional area of thefirst drain flow path and the second drain flow path can be furtherensured, and the valve case can be easily processed.

Another characteristic configuration resides in that the valve openingand closing timing control device includes a lock mechanism thatrestrains a relative rotation phase of the driven-side rotary body withrespect to the drive-side rotary body to an intermediate phase between amost retarded phase and a most advanced phase, in which the fluidsupplied to the lock mechanism is discharged from the first drain flowpath.

As in this configuration, the fluid discharge from the lock mechanism isalso used in the first drain flow path. Accordingly, it is not necessaryto separately provide a lock drain flow path extending in the rotationaxis direction of the valve case. Therefore, a sufficient flow pathcross-sectional area of the first drain flow path can be ensured.Further, since it is possible to discharge the fluid of the lockmechanism from the first drain flow path while discharging the fluid ofthe advance chamber or the retard chamber from the second drain flowpath, shift to the intermediate phase can be performed smoothly.

Another characteristic configuration resides in that the valve openingand closing timing control device includes a lock mechanism thatrestrains a relative rotation phase of the driven-side rotary body withrespect to the drive-side rotary body to a most retarded phase or a mostadvanced phase, in which the fluid supplied to the lock mechanism isdischarged from the first drain flow path.

As in this configuration, since the fluid discharge from the lockmechanism is also used in the first drain flow path, it is not necessaryto separately provide a lock drain flow path extending in the rotationaxis direction of the valve case. Therefore, a sufficient flow pathcross-sectional area of the first drain flow path can be ensured.

Another characteristic configuration resides in that the second drainflow path includes a through hole of the valve case along a directionintersecting the rotation axis direction.

Since the second drain flow path in this configuration is constituted bythe through hole of the valve case in the direction intersecting therotation axis direction, the flow path cross-sectional area can besufficiently ensured.

Another characteristic configuration resides in that the first drainflow path includes a hole portion along the rotation axis direction ofthe valve case.

As in this configuration, if the first drain flow path is constituted bythe hole portion in the rotation axis direction of the valve case, thesize of the hole portion may be changed according to a required flowpath cross-sectional area, and the flow path can be easily designed.

Another feature configuration resides in that the first drain flow pathis formed between an outer end portion of the spool and the valve case.

As in this configuration, if the first drain flow path is formed betweenthe outer end portion of the spool and the valve case, processing iseasier than when the first drain flow path is formed in the rotationaxis direction of the valve case.

Another characteristic configuration resides in that, when the spool isat one of a movement start position or a movement end position, thefluid is discharged from the first drain flow path, and when the spoolis at the other one of the movement start position or the movement endposition, the fluid is discharged from the second drain flow path.

As in this configuration, if the first drain flow path and the seconddrain flow path are provided when the spool is at the movement startposition and movement end position, positions of the phase control drainflow path can be easily set.

The principles, preferred embodiment and mode of operation of thepresent invention have been described in the foregoing specification.However, the invention which is intended to be protected is not to beconstrued as limited to the particular embodiments disclosed. Further,the embodiments described herein are to be regarded as illustrativerather than restrictive. Variations and changes may be made by others,and equivalents employed, without departing from the spirit of thepresent invention. Accordingly, it is expressly intended that all suchvariations, changes and equivalents which fall within the spirit andscope of the present invention as defined in the claims, be embracedthereby.

What is claimed is:
 1. A valve opening and closing timing control devicecomprising: a drive-side rotary body that rotates synchronously with acrankshaft of an internal combustion engine; a driven-side rotary bodythat is provided inside the drive-side rotary body in a state of beingcoaxial with a rotation axis of the drive-side rotary body and thatrotates integrally with a camshaft for opening and closing a valve; anadvance chamber and a retard chamber formed between the drive-siderotary body and the driven-side rotary body; a valve unit that includesa spool movable in a rotation axis direction and that controls supplyand discharge of fluid to and from the advance chamber and the retardchamber; a tubular valve case that has an internal space extending alongthe rotation axis inside the driven-side rotary body in a radialdirection and that houses the valve unit in the internal space; a firstdrain flow path through which the fluid is discharged from any one ofthe advance chamber or the retard chamber through the spool; and asecond drain flow path through which the fluid is discharged from theother one of the advance chamber or the retard chamber through thespool, wherein the first drain flow path and the second drain flow pathextend in directions intersecting each other at different positions inthe rotation axis direction.
 2. The valve opening and closing timingcontrol device according to claim 1, wherein in the valve case, thefirst drain flow path is formed to extend in the rotation axis directionand the second drain flow path is formed to extend in a radial directionorthogonal to the rotation axis direction.
 3. The valve opening andclosing control device according to claim 1, further comprising: a lockmechanism that restrains a relative rotation phase of the driven-siderotary body with respect to the drive-side rotary body to anintermediate phase between a most retarded phase and a most advancedphase, wherein the fluid supplied to the lock mechanism is dischargedfrom the first drain flow path.
 4. The valve opening and closing controldevice according to claim 2, further comprising: a lock mechanism thatrestrains a relative rotation phase of the driven-side rotary body withrespect to the drive-side rotary body to an intermediate phase between amost retarded phase and a most advanced phase, wherein the fluidsupplied to the lock mechanism is discharged from the first drain flowpath.
 5. The valve opening and closing control device according to claim1, further comprising: a lock mechanism that restrains a relativerotation phase of the driven-side rotary body with respect to thedrive-side rotary body to a most retarded phase or a most advancedphase, wherein the fluid supplied to the lock mechanism is dischargedfrom the first drain flow path.
 6. The valve opening and closing timingcontrol device according to claim 4, wherein the second drain flow pathincludes a through hole of the valve case along a direction intersectingthe rotation axis direction.
 7. The valve opening and closing timingcontrol device according to claim 5, wherein the first drain flow pathincludes a hole portion along the rotation axis direction of the valvecase.
 8. The valve opening and closing timing control device accordingto claim 6, wherein the first drain flow path includes a hole portionalong the rotation axis direction of the valve case.
 9. The valveopening and closing timing control device according to claim 5, whereinthe first drain flow path is formed between an outer end portion of thespool and the valve case.
 10. The valve opening and closing timingcontrol device according to claim 6, wherein the first drain flow pathis formed between an outer end portion of the spool and the valve case.11. The valve opening and closing timing control device according toclaim 1, wherein when the spool is at one of a movement start positionor a movement end position, the fluid is discharged from the first drainflow path, and when the spool is at the other one of the movement startposition or the movement end position, the fluid is discharged from thesecond drain flow path.
 12. The valve opening and closing timing controldevice according to claim 2, wherein when the spool is at one of amovement start position or a movement end position, the fluid isdischarged from the first drain flow path, and when the spool is at theother one of the movement start position or the movement end position,the fluid is discharged from the second drain flow path.
 13. The valveopening and closing timing control device according to claim 3, whereinwhen the spool is at one of a movement start position or a movement endposition, the fluid is discharged from the first drain flow path, andwhen the spool is at the other one of the movement start position or themovement end position, the fluid is discharged from the second drainflow path.
 14. The valve opening and closing timing control deviceaccording to claim 4, wherein when the spool is at one of a movementstart position or a movement end position, the fluid is discharged fromthe first drain flow path, and when the spool is at the other one of themovement start position or the movement end position, the fluid isdischarged from the second drain flow path.
 15. The valve opening andclosing timing control device according to claim 5, wherein when thespool is at one of a movement start position or a movement end position,the fluid is discharged from the first drain flow path, and when thespool is at the other one of the movement start position or the movementend position, the fluid is discharged from the second drain flow path.16. The valve opening and closing timing control device according toclaim 6, wherein when the spool is at one of a movement start positionor a movement end position, the fluid is discharged from the first drainflow path, and when the spool is at the other one of the movement startposition or the movement end position, the fluid is discharged from thesecond drain flow path.
 17. The valve opening and closing timing controldevice according to claim 7, wherein when the spool is at one of amovement start position or a movement end position, the fluid isdischarged from the first drain flow path, and when the spool is at theother one of the movement start position or the movement end position,the fluid is discharged from the second drain flow path.
 18. The valveopening and closing timing control device according to claim 8, whereinwhen the spool is at one of a movement start position or a movement endposition, the fluid is discharged from the first drain flow path, andwhen the spool is at the other one of the movement start position or themovement end position, the fluid is discharged from the second drainflow path.
 19. The valve opening and closing timing control deviceaccording to claim 9, wherein when the spool is at one of a movementstart position or a movement end position, the fluid is discharged fromthe first drain flow path, and when the spool is at the other one of themovement start position or the movement end position, the fluid isdischarged from the second drain flow path.
 20. The valve opening andclosing timing control device according to claim 10, wherein when thespool is at one of a movement start position or a movement end position,the fluid is discharged from the first drain flow path, and when thespool is at the other one of the movement start position or the movementend position, the fluid is discharged from the second drain flow path.